The present invention provides a simple method to accelerate LUN snapshots and decrease their bandwidth requirements in a block-level archiving system. The same method also allows for savings in disk reconstruction or replacement time in an archiving RAID system. The method allows LUN snapshots to be effected at a lower level of the storage device has the advantage of saving bandwidth where it counts most: the host internal and I/O busses.
Referring to FIG. 1, providers of block-level storage provide their version of snapshot and/or related services like volume copy implemented by a disk controller 20 controlling disks 30, and providing a host 10 access to the disks 30. The storage controller 20 interconnects with the host 10 via host side pipes 12. The storage controller 20 also interconnects with the disks 30 via disk side pipes 14. The storage controller 20 further interconnects with other controllers via additional pipes 16 for, inter alia, shadowing purposes. Equivalent services can be implemented at the host system level where knowledge of the file system can allow for a much finer control of the process. However, such services consume bandwidth where it counts most: the host internal and I/O busses.